/**********************************************************

@description:
*File Name:a1.c
*Author: ydx
*mail: yudongxiang93@163.com
*Create Time: Thu 05 Jun 2025 09:42:47 PM CST
**********************************************************/
#include<stdio.h>
#include<string.h>
void str_cpy(char *dest,const char *src){
	while(*src){
		*dest++=*src++;
	}
	*dest='\0';
}
int main(){
	char *src="hello";
	char dest[10];
	str_cpy(dest,src);
	printf("%s\n%s\n",src,dest);
	strcat(dest,"world");
	printf("%s",dest);
	char *p="";
	char *p1=NULL;
	if(!*p){
		printf("is NULL\n");
	}
	printf("%d\n",'0'+5);
}
